The structures of ruthenium(l1) complexes formed in solution from [RuX{(S)-binap}(arene)]Y (S) -3 (X, Y = halide and/or BF,-; binap = 2,2'-bis(diphenylphosphino)-l,l '-binaphthyl; arene = benzene or p-cymene) depend on the solvent. In acetonitrile-methanol (1 :predominantly formed, while monocationic species [RuX{(S)-binap}(MeCN)JX ( S ) -6 (X = CI a, Br b or I c ) were observed in acetonitrile. These mono-and di-cationic species could not be isolated pure, while [RuCI,{(S)-binap}(MeCN),] (S)-5 was isolated from (S)-4a or (S)-6a upon concentration of the reaction mixture. In methanol without donor molecules such as acetonitrile, cationic trinuclear complexes [Ru,X,{(S)-binap},JY (S)-7 (X = Y = CI a; X = CI, Y = BF, b or X = Y = Br c ) were exclusively formed by heating at 60 "C or UV irradiation of a solution of (S)-3. The structure of (S)-7 was characterized by spectral data and an X-ray crystallographic analysis of (S) -7b [orthorhombic, space group P2,2,2,, a = 26.328(5), b = 18.1 40(3), c = 26.374(4), Z = 4, R' = 0.0831. The relationship between the structure of the Ru"( binap) complexes and their catalytic activities for asymmetric hydrogenation of methyl 3-28 Kyoto Program Package for X-Ray Crystal Structure Analysis, 233.
